Laser Raman spectroscopic studies of several types of cataract will be performed using intact lenses in order to test the protein orientational disorder theory of cataract formation and in order to determine the biochemical and microstructural alterations that produce lens opacities. The types of cataract to be studied include cold cataracts, pressure induced cataracts, rat galactose cataracts and human senile cataracts. The observed Raman spectra will be correlated with turbidity which will be controlled. Upon completion of the in vitro studies, Raman spectra of the lenses of cats and monkeys will be recorded in vivo while exposing the animals to radiation doses significantly below the threshold for retinal damage. The development of an in vivo Raman spectroscopic technique might allow for the determination of biochemical and molecular changes which are precursors of human cataracts.